Your Comfort is Our Concern
Welcome to the patient education section of Aspect Medical's corporate website. The descriptions and resources you will find on these pages are meant to serve as an information resource for you - the healthcare consumer. Whether you are facing a medical decision yourself, or conducting research for a friend or family member, we hope you find the information provided on these pages to be useful. It is important to understand that this information is provided for informational purposes only and must never be considered medical advice. Always consult with your physician if you have any concerns regarding your medical situation.
History of anesthesia
Anesthesia, the general or localized insensitivity to pain or other sensation, revolutionized the practice of medicine more than a century ago. Both an art and a science, the purpose of administering general anesthesia during surgery is to render the patient unconscious, prevent pain and ensure a quiet surgical field with minimal movement during a surgical procedure. Before the discovery of anesthesia, even relatively simple procedures, such as an appendectomy were painful and often fatal. With the discovery in the mid-1800s that nitrous oxide ("laughing gas") and ether made patients insensitive to pain, the practice of anesthesia was born, making surgery a viable option for many conditions. Today, a combination of anesthetic drugs accomplishes the needed results: analgesic drugs provide pain relief; muscle relaxants ensure the patient doesn't move; and hypnotic drugs make the patient unconscious. An estimated 20 million patients undergo surgery with general anesthesia every year in the U.S. alone.
Challenge of anesthesia
While anesthesia made surgery more common practice, it brought about a new need in the medical community - the monitoring of patients who have undergone general anesthesia. Until recently, there was no direct means of assessing a patient's level of consciousness during surgery. For years, anesthesia providers relied on multiple monitors to measure the state of the patient during surgery, including heart rate, blood pressure and a variety of other vital signs. However, none of these measures directly correlated with consciousness. Clinicians, therefore, were forced to rely solely on the indirect measurements to gauge the appropriate dosage for each patient to remain unconscious and free of pain during surgery. In addition, standard dosages based on the anesthetic needs of an average, middle-aged male were used to guide administration of anesthetics. These standards were not necessarily appropriate for other patients, including women, patients of different ages and those with serious underlying diseases, leaving patients at risk for under- and over-sedation.
Implications of under- or over-sedation
The inability to directly measure the effect of anesthesia on each individual certainly presented some serious challenges. Cases of under-sedation and over-sedation can lead to adverse clinical and economic outcomes. In rare and extreme cases, patients who receive too little anesthesia might experience intraoperative awareness, which can have long-term emotional implications, including post-traumatic stress disorder. More common is the problem of patients receiving more anesthetic than is needed because a patient requires less drug than the standard dosage, which has been set at levels to prevent awareness in the majority of the population. Receiving too much drug can result in longer wake-up times, unnecessarily prolonged recoveries and, frequently, nauseous recoveries. No specific data have been published on the number of patients who receive more anesthesia than they need, but estimates place this number in the millions.
The BIS Solution
The practice of anesthesia changed dramatically in 1996. For years, clinicians and researchers had searched for ways to translate the information from the electroencephalogram (EEG) - a waveform representing the electrical activity of the brain - into an assessment of a patient's consciousness during surgery. With its introduction of Bispectral Index® (BIS®) technology, Aspect Medical Systems became the first company to provide a commercially available measure to assess consciousness during anesthesia and sedation. The first technology that directly monitors a patient's level of consciousness, BIS helps anesthesia providers determine and administer the precise amount of drug to meet the needs of each individual patient, thus providing significant benefits for patients and healthcare institutions. Such benefits may include:
- Patients receive lower doses of certain anesthetics or sedatives
- Patients wake up faster
- Patients are more likely to bypass the stage one post anesthesia care unit (PACU), progressing directly to a step-down PACU
- Patients are eligible for discharge from the PACU faster
- Patients experience higher-quality recoveries
- Patients are less likely to experience intra-operative awareness with recall
- Hospitals can reduce costs, including the costs of anesthetics and/or sedatives
Today and Beyond
Today, BIS provides doctors and nurses with reliable information about the dynamic and patient-specific effects that drugs have on the brain, allowing affirmation of clinical decisions and more precise dosing of anesthesia and sedatives. Currently used in 61 percent of the top US hospitals (U.S. News & World Report), BIS has clearly established the process by which subsequent technologies will be validated and is leading the way to a better understanding of the brain.
